3-formylchromones

ABSTRACT

Novel 3-formylchromone derivatives are disclosed, substituted on the 5,6,7, or 8 positions by one or more of the following substituents: halogen, hydroxy, lower alkyl, lower alkoxy, lower acyl, lower acyloxy, or methylenedioxy. The corresponding 3-acetal or 3-hydrazone derivatives of the carboxaldehyde group are also disclosed. These compounds, and pharmaceutical compositions containing these compounds are useful for the treatment of allergic conditions and for the treatment of hyperacidity.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of copending U.S. applicationSer. No. 352,149, filed Apr. 18, 1973, now abandoned.

SUMMARY OF THE INVENTION

This invention relates to novel chromone derivatives having the formulaI: ##STR1## wherein R₁ represents halogen, hydroxy, lower alkyl, orlower alkoxy; R₂ represents hydrogen, or lower alkyl; R₃ representshydrogen, lower acyl, or lower acyloxy; and wherein R₁ and R₂ togethermay form a methylenedioxy ring; and the corresponding 3-acetal or3-hydrazone derivatives thereof. These compounds, and pharmaceuticalcompositions containing these compounds, are useful for the treatment ofallergic conditions and for the treatment of hyperacidity.

DETAILED DESCRIPTION OF THE INVENTION

The novel compounds of this invention have the general formula I:##STR2## wherein R₁ represents halogen, hydroxy, lower alkyl, or loweralkoxy; R₂ represents hydrogen, or lower alkyl; R₃ represents hydrogen,lower acyl, or lower acyloxy; and wherein R₁ and R₂ together may form amethylenedioxy ring; and the corresponding 3-acetal or 3-hydrazonederivatives thereof. As a particularly active class of compounds, theremay be mentioned those having the formula I above, wherein R₁ representsbromine, hydroxy, methyl, or methoxy; R₂ represents hydrogen or methyl,and R₃ represents hydrogen, acetyl or acetoxy; and wherein R₁ and R₂together may form a methylenedioxy ring; and the corresponding 3-acetalor 3-hydrazone derivatives thereof.

In formula I above, and in all subsequent formulas, the R groupsubstituents may be described as follows: the term "lower alkyl" ismeant to include lower aliphatic hydrocarbons having 1 to 4 carbon atomsin the carbon chain, such as methyl, ethyl, propyl, isopropyl, butyl, orisobutyl. This definition for lower alkyl also applies to the loweralkyl portion of "lower alkoxy."

The term halogen is meant to include bromine, chlorine, iodine, andfluorine.

The acyl in the term "lower acyloxy" is meant to include lower alkylcarboxylic acids wherein the "lower alkyl" moiety has the abovedescribed meaning. Similarly, the term "lower acyl" is meant to includeacyl groups derived from such aformentioned lower alkyl carboxylicacids.

Compounds of this invention having the general formula I above have beenfound to reduce histaminic responses to antigen challenge by inhibitingantibody-antigen reactions in mammals such as rats or guinea pigs uponoral or parenteral administration. When tested in accordance with theprocedure of Mota, Life Sciences, 7, 465, (1963) and Ovary, Proc. Soc.Exptl. Biol. Med., 81, 584, (1952), therapeutic compositions containingthe compounds of this invention are effective at dosages of 5 mg to 50mg/kg of body weight.

Pharmaceutical compositions containing the compounds of this inventionare therefore useful in the managesment of allergic reactions such asbronchial asthma. To treat bronchial asthma, a dose of 5 mg to 50 mg/kg,administered orally or parentereally is suggested; in addition, aerosoladministration of lower doses may be used. The dosage may be varieddepending upon severity of the condition and the weight, age and sex ofthe patient being treated.

In use, the compounds of this invention may be combined with aparenterally acceptable vehicle, such as a gum tragacanth salinesuspension, to provide dosage forms suitable for parenteraladministration; or they may be combined with pharmaceutical diluentssuch as lactose, cornstarch, and the like and formulated into tablet orcapsule dosage forms. In order to enhance their therapeutic spectrum,the compounds of this invention may be combined with sympathomimeticagents such as isoprenaline or combined with steroids such as cortisoneand its derivatives.

The compounds of this invention also exhibit antisecretory effects andare therefore useful in relieving gastric hyperacidity. Gastrichyperacidity has generally been described as a factor which contributesto peptic ulcer. The compounds of this invention, when administered tomammals in a manner as described below, have been found to inhibit thegastric secretion of hydrochloric acid and are therefore effective inreducing the resulting acidity in the stomach.

At a dosage of 20 mg/kg administered intraperitoneally, the subjectcompositions are effective in reducing gastric acidity in the pylorusligated rat when tested according to the procedure of H. Shay,Gastroenterology, 5, 43, (1945).

Pharmaceutical compositions containing the compounds of this invention,are thus indicated in the management of gastric hyperacidity and thetreatment of peptic ulcer resulting from such hyperacidity. Forparenteral administration, the pharmaceutical composition of thisinvention may be administered as aqueous suspensions for intramuscularinjection. These are prepared, for example, by suspending the activeingredient in sterile water and packaged in ampules so as to provide aconcentration of 1,000 mg of the active ingredient per dosage unit.

Generally speaking, the dose required to effectively relieve gastrichyperacidity is within the range of 20 mg/kg of body weight of themammal being treated. This dosage regimen may be varied depending uponthe condition of the patient.

In addition to the above mentioned utilities, the compounds of thisinvention are useful as intermediates for the preparation of othertherapeutically useful chromone derivatives, such as the correspondingcarboxylic acids, esters, nitriles, oximes or acetals.

Compounds of the invention having formula I above may be prepared by oneof three different procedures.

According to one process described in copending application Ser. No.352,133, filed Apr. 18, 1973, now U.S. Pat. No. 3,912,760, compounds ofthe formula I are prepared by treating a compound of the formula II:##STR3## with an acid anhydride of the formula III:

    (R.sub.4 CH.sub.2 CO).sub.2 O                              III

and boron trifluoride compound (preferably boron trifluoride etherate)to provide an intermediate of the formula IV: ##STR4## wherein R₁represents hydroxy, lower alkyl, or lower alkoxy; R₂ representshydrogen, or lower alkyl; R₃ represents hydrogen, lower acyl, or loweracyloxy, and wherein R₁ and R₂ together may form a methylenedioxy ring,and R₄ represents hydrogen or lower alkyl; and treating intermediate IVwith a Vilsmeier reagent selected from the group consisting ofphosphorus oxychloride together with dimethylformamide, and phosphorusoxychloride together with dimethylacetamide, followed by hydrolysis toyield the novel substituted 3-formylchromones of this invention.

A second method for preparing the compounds of this invention describedin part by Durden, J. A. et al., in J. Org. Chem. 30: 1684-1687 (1965),involves the reaction of 2-hydroxyacetophenone with acetic anhydride andboron trifluoride to provide2,2-difluoro-4-methyl-1,3,2-benzodioxaborin. By subjecting thisintermediate to reaction with the Vilsmeier reagent as taught in thenovel process of co-pending application Ser. No. 352,133, filed Apr. 18,1973, now U.S. Pat. No. 3,912,760, one obtains 3-formylchromone.

A third method by which the substituted 3-formylchromone compounds ofthis invention may be prepared is described in copending applicationSer. No. 351,915, filed Apr. 18, 1973, now abandoned in favor ofcontinuation-in-part application U.S. Ser. No. 480,984, filed June 19,1974, now U.S. Pat. No. 3,886,183, and involves the oxidation of acompound of the general formula V: ##STR5## wherein R₁ representshalogen, lower alkyl, or lower alkoxy; with an oxidizing agent such assodium dichromate/glacial acetic acid combination, concentrated nitricacid, or potassium persulfate, to obtain the correspondingly substituted3-formyl chromones of this invention. Starting materials of formula Vabove, and various derivatives thereof containing one or moresubstituents on the phenyl ring of the 3-hydroxymethylchromone structureare described in co-pending application Ser. No. 112,765, filed Feb. 4,1971, now abandoned; and in its continuation-in-part, Ser. No. 309,329,filed Nov. 24, 1972, now U.S. Pat. No. 3,798,240. Typical startingmaterials described in aforementioned Ser. Nos. 112,765 and 309,329include:

3-(hydroxymethyl)chromone;

6-hydroxy-3-(hydroxymethyl)chromone;

6-chloro-3-(hydroxymethyl)chromone;

3-(hydroxymethyl)-6-iodochromone;

3-(hydroxymethyl)-6-methoxychromone;

6-bromo-3-(hydroxymethyl)chromone;

7-chloro-3-(hydroxymethyl)chromone;

3-(hydroxymethyl)-8-isopropylchromone;

3-(hydroxymethyl)-7-methoxychromone;

3-(hydroxymethyl)-8-methoxychromone;

8-chloro-3-(hydroxymethyl)chromone;

6-fluoro-3-(hydroxymethyl)chromone;

3-(hydroxymethyl)-6-(1,1,3,3-tetramethylbutyl)chromone;

3-(hydroxymethyl)-8-methylchromone;

3-(hydroxymethyl)-6,8-dimethylchromone;

3-(hydroxymethyl)-6-methylchromone; and

3-(hydroxymethyl)-5-methoxychromone.

The above-mentioned compounds V are prepared by reacting correspondinglysubstituted compounds having the formula VI: ##STR6## wherein R₁ is asdefined above, with 2 moles of formaldehyde under basic conditions toobtain an intermediate compound having the formula VII: ##STR7## whereinR₁ is as defined above; and treating compound VII thermally to eliminatemethylsulfinic acid (CH₃ SOH) and obtain the desired starting materialsV. Compounds having the formula VI above are prepared by (A) reactingdimethylsulfoxide with sodium hydride in an inert solvent; (B) adding toreaction mixture (A) an appropriately substituted salicylic ester; (C)maintaining the reaction mixture of (B) at a temperature of up to 50° C;(D) reducing the solubility of the sodium salt reaction product of (C)by the addition of a non-polar solvent; and (E) collecting theprecipitate formed. Appropriately substituted salicylic esters used inthis process are known or easily prepared by known methods. A similarprocess has been reported by Becker et al., in J.A.C.S. 85: 3410 (1963).

To further illustrate the practice of this invention, the followingexamples are included:

EXAMPLE I ##STR8## Method A -- General Procedure and Preparation of3-formyl-6-methylchromone

A solution of Vilsmeier Reagent is prepared by the dropwise addition of153 g. (1.0 mole) of phosphorus oxychloride to ice colddimethylformamide (365 g., 5 moles). The temperature is maintained below10° C by use of a cooling bath. One-half mole of the appropriate boronfluoride complex is added and the mixture stirred for 15 minutes, thenheated on a steam bath for 2 hours. The reaction mixture is poured ontoabout 3 liters of cold water. After standing at room temperature forseveral hours, the mixture is filtered to yield the desiredsubstituted-3-formyl chromone derivative. Using this procedure, thefollowing compounds are prepared: 3-formyl-6-methylchromone is preparedfrom 2,2-difluoro-4,6-dimethyl-1,3,2-benzodioxaborin, according toprocedure A, to obtain a product having mp 171°-173° C.

Anal. Calcd. for C₁₁ H₈ O₃ : C, 70.21; H, 4.29; Found: C, 69.95; H,4.33.

EXAMPLE II ##STR9## Preparation Of 7-Methoxy-3-formylchromone

7-Methoxy-3-formylchromone is prepared from2,2-difluoro-7-methoxy-4-methyl-1,3,2-benzodioxaborin, according toprocedure A of Example I, to obtain a product having mp 188°-190° C.

Anal. Calcd. for C₁₁ H₈ O₄ : C, 64.70; H, 3.95; Found: C, 64.47; H,4.09.

EXAMPLE III ##STR10## Preparation Of7-Methoxy-4-oxo-4H-1-benzopyran-3-carboxaldehyde-2-pyridylhydrazone

7-Methoxy-4-oxo-4H-1-benzopyran-3-carboxaldehyde-2-pyridylhydrazone isprepared by reacting the product of Example II,3-formyl-7-methoxychromone, with 2-hydrazinopyridine, to obtain aproduct having mp 171°-173° C.

Anal. Calcd. for C₁₆ H₁₃ N₃ O₃ : C, 65.08; H, 4.44; N, 14.23; Found: C,64.95; H, 4.66; N, 14.59.

EXAMPLE IV ##STR11## Preparation Of 3-Formyl-6,7-dimethylchromone

3-Formyl-6,7-dimethylchromone is prepared from2,2-difluoro-4,6,7-trimethyl-1,3,2-benzodioxaborin, according toprocedure A in Example I, to obtain a product having mp 154°-156° C.

Anal. Calcd. for C₁₂ H₁₀ O₃ : C, 71.28; H, 4.99; Found: C, 71.11; H,4.92.

EXAMPLE V ##STR12## Preparation Of 3-Formyl-6,7-methylenedioxychromone

3-Formyl-6,7-methylenedioxychromone is prepared from2,2-difluoro-4-methyl-1,3-dioxolo[4,5-g]1,3,2-benzodioxaborin, accordingto procedure A of Example I, to obtain a product having mp 232°-233° C.

Anal. Calcd. for C₁₁ H₆ O₅ : C, 60.56; H, 2.77; Found: C, 60.80; H,2.79.

EXAMPLE VI ##STR13## Preparation Of8-Oxo-8H-1,3-dioxolo[4,5-g][1]benzopyran-7-carboxaldehyde diethyl acetal

8-Oxo-8H-1,3-dioxolo[4,5-g][1]benzopyran-7-carboxaldehyde diethyl acetalis prepared by reacting the product of Example VIII,3-formyl-6,7-methylenedioxychromone, with ethanol to obtain a producthaving mp 123°-125° C.

Anal. Calcd. for C₁₅ H₁₆ O₆ : C, 61.64; H, 5.52; O, 32.85; Found: C,61.70; H, 5.51; O, 33.11.

EXAMPLE VII ##STR14## Preparation Of8-Acetoxy-3-formyl-7-methoxychromone

8-Acetoxy-3-formyl-7-methoxychromone is prepared from8-acetoxy-2,2-difluoro-7-methoxy-4-methyl-1,3,2-benzodioxaborin,according to procedure A of Example I, to obtain a product having mp160°-161° C.

Anal. Calcd. for C₁₃ H₁₀ O₆ : C, 59.54; H, 3.84; Found: C, 59.42; H,3.80.

EXAMPLE VIII ##STR15## Preparation of6-Acetyl-3-formyl-7-hydroxychromone

6-Acetyl-3-formyl-7-hydroxychromone is prepared from6-acetyl-2,2-difluoro-7-hydroxy-4-methyl-1,3,2-benzodioxaborin,according to procedure A of Example I.

EXAMPLE IX ##STR16## Preparation of8-Acetyl-3-formyl-5,7-dimethoxychromone

8-Acetyl-3-formyl-5,7-dimethoxychromone is prepared from8-acetyl-2,2-difluoro-5,7-dimethoxy-4-methyl-1,3,2-benzodioxaborin,according to procedure A of Example I.

EXAMPLE X ##STR17## Method A -- Preparation Of 3-Formylchromone

3-Formylchromone is prepared from2,2-difluoro-4-methyl-1,3,2-benzodioxaborin, according to procedure A ofExample 1, to obtain a product having mp. 149°-151° C.

Anal. Calcd. for C₁₀ H₆ O₃ : C, 68.96; H, 3.47; Found: C, 69.20; H,3.69.

[Compound prepared by another method, reported in Eiden, F. et al.,Arch. der Pharm. 300: 806-810 (1967)]

EXAMPLE XI ##STR18## Method B -- Preparation Of 6-Bromo-3-formylchromone

A warm (40° C.) solution of 29.8 g. (0.1 mole) of sodium dichromatedihydrate in 80 ml of glacial acetic acid is added over a 5-minuteperiod to a stirred, warm (60° C.) solution of 25.5 g. (0.1 mole) of6-bromo-3-(hydroxymethyl)chromone in 300 ml of glacial acetic acid. Thetemperature rises to 72° C. After one-half hour, water (1400 ml) isadded and the mixture is heated at 80° C. for a few minutes. The mixtureis cooled and filtered to give 13.6 g. (54%) of good quality aldehyde.Recrystallization from ethyl acetate gives pure 6-bromo-3-formylchromonehaving mp 186°-188° C.

Anal. Calcd for C₁₀ H₅ BrO₃ : C, 47.46; H, 1.99; Br, 31.58; Found: C,47.19; H, 1.99; Br, 31.56.

EXAMPLE XII ##STR19## Method B -- Preparation Of3-Formyl-8-methoxychromone

A quantity of 41.2 g (0.2 mole) of 3-(hydroxymethyl)-8-methoxychromoneis heated with 600 ml of glacial acetic acid to 50° C to dissolve. Withstirring, a warm solution (70°) of 59.6 g (0.2 mole) of sodiumdichromate dihydrate in 200 ml of glacial acetic acid is added over aperiod of 5 minutes, preventing the temperature from going over 80° Cwith cooling. After 20 minutes, about one-half of the acetic acid isdistilled off at reduced pressure. Water (500 ml) is added toprecipitate 13.1 g (32%) of crude aldehyde. Upon addition of more waterto the filtrate, an additional 6.4 g of crude is obtained; total weight19.4 g (48%). Purification is effected by dissolution in 150 ml of warmchloroform and filtration through a layer of silica gel; mp 171°-175° C.Recrystallization from acetonitrile gave pure aldehyde; mp 174°-176° C.

Anal. Calcd. for C₁₁ H₈ O₄ : C, 64.70; H, 3.95; Found: C, 64.81; H,3.91.

EXAMPLE XIII ##STR20## Method B -- Preparation Of 3-Formylchromone

A quantity of 35.2 g. (0.2 mole) of 3-(hydroxymethyl)chromone isdissolved in 250 ml of concentrated nitric acid with stirring at 25° C.There is no initial heat of reaction. The temperature gradually rises to30° C over the next several minutes and is kept there for about fiveminutes with ice-acetone bath cooling. Water, 600 ml, is added to thereaction solution. The separated, pale yellow solid is filtered, washedwell with water and dried to give 25 g. of crude aldehyde melting at145°-148°.

Purification to remove a minor, slow-moving spot on thin-layerchromatography (ethylacetate-silica gel) is effected by dissolution ofabove 25 g. in 500 ml of methylene chloride and filtration through asilica gel column about 10 cm. long by about 5.0 cm. diameter) andwashing with 500 ml methylene chloride. Concentration of the filtrategives 20.0 g. (68%) of pure aldehyde melting at 151°-152° C.

Anal. Calcd for C₁₀ H₆ O₃ : C, 68.97; H, 3.47. Found: C, 68.76; H, 3.19.

[Compound prepared by another method, reported in Eiden, F. et al.,Arch. der Pharm. 300: 806 (1967)]

EXAMPLE XIV Evaluation of Gastric Anti-ulcer Activity (in vivo)

Male rats are subjected to ligation of the gastropyloric junction. Thisoperation causes the secretion of large quantities of gastric juicewhich leads to mucosol erosion in the ruminal area of the rat's stomach.The compound to be tested is given intraperitoneally (I.P.) at the timeof ligation. The rats are sacrificed after 18 hours and their stomachesare removed. The efficacy of the test compound is evaluated by itsability to minimize the erosion of stomach mucosa and/or decrease thevolume of acid secretions below harmful levels. Results with compoundsof Examples X* and XI** are indicated in Table I below:

                  TABLE I                                                         ______________________________________                                                                       % Decrease of                                  Compound  Dose mg/kg  Route    Acid Volume                                    ______________________________________                                        Ex. X     20          I.P.     47.2                                           Ex. XI    20          I.P.     31.7                                           ______________________________________                                    

EXAMPLE XV Anti-allergy Evaluation In The Passive Cutaneous Anaphylaxis(PCA)

Rats, passively sensitized with reogin type antibodies, are pretreatedwith the test compound and challenged with antigen-Evans blue mixture.After 30 minutes the animals are sacrificed and the skin containing thefour sensitizing sites is removed. The activity is evaluated by theability of the compound to minimize tissue reaction to challenge. Thisis indicated by the decrease in size and coloration of the areas aroundinjection sites when compared to controls. Results with compounds ofExamples X* and XI** are indicated in Table 2 below:

                  TABLE 2                                                         ______________________________________                                                                      Inhibition of                                                                 Passive Cutaneous                               Compound Dose mg/kg  Route    Anaphylaxis                                     ______________________________________                                        Ex.XI     50         I.P.     51%                                             Ex. X    100         Per Os   35%                                             ______________________________________                                    

Human atopic allergy has been shown to be due to a specific class ofantibody (IgE), which is heat labile and fixes for long times in theskin after passive transfer with the serum of sensitive individuals. Asimilar type of antibody is found in the rat. This antibody isnon-precipitating. Therefore, it is a most unique type. This antibodyreleases histamine and serotonin from mast cells in the rat as it doesin the human. Thus, any drug which interferes with the passive cutaneousanaphylaxis reaction in the rat becomes of interest for treatment ofhuman allergy.

EXAMPLE XVI ##STR21## Preparation of 3-Formyl-8-methoxychromone

8-Methoxy-3-formyl chromone is prepared from2,2-difluoro-8-methoxy-4-methyl-1,3,2-dioxaborin, according to procedureA of Example I, to obtain a product having a melting point of 174°-176°C.

Anal. Calcd. for C₁₁ H₈ O₄ : C, 64.70; H, 3.95; Found: C, 64.81; H,3.91.

We claim:
 1. 6-Acetyl-3-formyl-7-hydroxychromone. 2.8-Acetyl-3-formyl-5,7-dimethoxychromone.